Hello, I have a had a problem for awhile with a error P401 EGR(Insufficient Exhaust Gas Flow). I have replaced eveything ERG valve, feedback sending unit, solenoid, replaced every piece rubber hose from the intake to all of the vaccum resevoirs . Took it to Ford they ran a diagnostic(the same thing I did with my AutoXray) but they charge me $130.00 and said my ports were dirty. I took off the tube from the exhaust manifold to EGR valve. Wire brushed Hi & Ref ports as well as the lenght of the tube. Blew it it out with shop air still
P401. Took truck to Midas cats ok. But a mechanic still thought it was the cats, replaced the cats no joy. Voltage is good on supply side of solenoid but only .347 on wire to PCM. Checked wiring all the way back to PCM ok. Any ideas?

mark333

 

Fill in your information so we know what truck year engine like mine is in the upper right corner. Maybe its the DPFE. the dealer should have found that though.

 

give us info on the truck and i can post up a pinpoint test.

 

Did you just clean the exhaust-to-EGR pipe, or did you also clean the ports on the 90° intake manifold adapter where the EGR attaches to? Those ports typically clog up too and can cause a P0401 code.
Another suspect would be the DPFE sensor as jethat posted or possibly the hoses leading up to it too. Don't bother with an aftermarket DPFE sensor...go with genuine Motorcraft one, they seem to last longer than the aftermarket ones.

If you haven't already, I'd try cleaning the ports on the manifold first, then try the DPFE and/or it's hoses.

 

Gee, thanks for your support Bindernut.

mark333 We know the problem and its relatively easy fix - Fill in your info @ your profile so it displays like our s does. That gives us your vehicle info, its needed of course

 

DPFE, almost any time a Ford gets an EGR code its a faulty DPFE sensor.

Well i shouldnt say that, cause on the 4.6 they can have cloged EGR passages under the throttle body on like crown vics and stuff. But anyway, 80% of the time I get a EGR code on any ford its a DPFE.

 

Not necessarily - specially if it's a 4six.

Fill in your info mark333

 

so i'm not the only one with this problem
my 4.6 has 'bout 120000 miles on it, check engine light
is on ,P401 EGR(Insufficient Exhaust Gas Flow),changed egr valve,

as Bindernut posted
"Did you just clean the exhaust-to-EGR pipe, or did you also clean the ports on the 90° intake manifold adapter where the EGR attaches to? Those ports typically clog up too and can cause a P0401 code.
Another suspect would be the DPFE sensor as jethat posted or possibly the hoses leading up to it too. Don't bother with an aftermarket DPFE sensor...go with genuine Motorcraft one, they seem to last longer than the aftermarket ones."

where is the DPFE located?

 

Before you spend any money on a DPFE, remove the throttle body--relatively easy job, only 4 bolts involved and disconnecting throttle cable, cruise control cable, some vacuum lines, one connection to the IAC (if memory serves), and the EGR. I'll bet you five dollars against a stale breadstick your ports from the EGR into the TB are clogged up INSIDE the TB. Turn the TB over and take a look--prepare to gasp in horror. Went through the same thing a while back with a '98 F150 4.6L with only 82000 on it. The ports were completely clogged--the clogs/residue were actually sticking out a good 4-5 mm's inside the TB. Don't even attempt to get this done right with TB still on--waste of time. Remember to clean mounting surfaces, replace gasket, and make all vac connections when reinstalling. And buy at least 3 cans of carb/choke cleaner before you start--you're going to need them. A good little wire brush shaped like a baby bottle washer is a big help and maybe some pipe cleaners. Hope this helps---The Vinman

 

Replace the DPFE valve. Ford had a run of bad DPFE valves. My 02 4.6L did the same thing, changed DPFE and and cleaned EGR valve and passages and truck ran better than new.

 

Just wanted to say thanks for everyone's suggestions. It was the the ports in the throttle body 90 deg sub-assembly. They were stuff to the max. I wish I would have posted this question sooner. But I got all new parts and the engine is running like brand new. Thanks to all.

Regards

Mark